There are two main categories of virtualization: 1) Computing Machine Virtualization 2) Resource Virtualization.
Computing machine virtualization involves definition and virtualization of multiple operating system (OS) instances and application stacks into partitions within a host system.
Resource virtualization refers to the abstraction of computer peripheral functions. There are two main types of Resource virtualization: 1) Storage Virtualization 2) Memory-Mapped I/O Virtualization.
Storage virtualization involves the abstraction and aggregation of multiple physical storage components into logical storage pools that can then be allocated as needed to computing machines. An example of storage virtualization is the iSCSI protocol.
Examples of Memory-Mapped I/O Virtualization are exemplified by PCI Express and applicant's i-PCI technology.
PCIe I/O Virtualization (IOV)
The PCI Special Interest Group (SIG) has defined single root and multi-root I/O virtualization sharing specifications. Of specific interest is the multi-root specification. The multi-root specification defines the means by which multiple hosts, executing multiple systems instances on disparate processing components, may utilize a common PCI Express (PCIe) switch in a topology to connect to and share common PCI Express resources.
The PCI Express resources are accessed via a shared PCI Express fabric. The resources are typically housed in a physically separate enclosure or card cage. Connections to the enclosure are via a high-performance short-distance cable as defined by the PCI Express External Cabling specification. The PCI Express resources may be serially or simultaneously shared.
A key constraint for PCIe I/O virtualization is the severe distance limitation of the external cabling. There is no provision in PCIe I/O for the utilization of networks for virtualization.
i-PCI
This technology of the present applicant builds and expands on technology introduced as “i-PCI” in commonly assigned copending U.S. patent application Ser. No. 12/148,712, the teachings of which are incorporated herein by reference. This patent application presents i-PCI as a new technology for extending computer systems over a network. The disclosed i-PCI protocol includes a hardware, software, and firmware architecture that collectively enables virtualization of host memory-mapped I/O systems. For a PCI-based host, this involves extending the PCI I/O system architecture based on PCI Express.
The i-PCI protocol advantageously extends the PCI I/O System via encapsulation of PCI Express packets within network routing and transport layers and Ethernet packets and then utilizes the network as a transport. The network is made transparent to the host and thus the remote I/O appears to the host system as an integral part of the local PCI system architecture. The result is a virtualization of the host PCI System. The i-PCI protocol allows certain hardware devices (in particular I/O devices) native to the host architecture (including bridges, I/O controllers, and I/O cards) to be located physically remote to the host. FIG. 1 shows a detailed functional block diagram of a typical host system connected to multiple remote I/O chassis using i-PCI. An i-PCI host bus adapter card [101] installed in a host PCI Express slot [102] interfaces the host to the network. An i-PCI remote bus adapter card [103] interfaces the remote PCI Express bus resources to the network.
There are three basic implementations of i-PCI:
1. i-PCI: This is the TCP/IP implementation, utilizing IP addressing and routers. This implementation is the least efficient and results in the lowest data throughput of the three options, but it maximizes flexibility in quantity and distribution of the I/O units. FIG. 2 depicts an i-PCI IP-based network implementation block diagram.
2. i(e)-PCI This is the LAN implementation, utilizing MAC addresses and Ethernet switches. This implementation is more efficient than the i-PCI TCP/IP implementation, but is less efficient than i(dc)-PCI. It allows for a large number of locally connected I/O units. Refer to FIG. 3 for an i(e)-PCI MAC-Address switched LAN implementation block diagram.
3. i(dc)-PCI. Referring to FIG. 4, this is a direct physical connect (802.3an) implementation, utilizing Ethernet CAT-x cables. This implementation is the most efficient and highest data throughput option, but it is limited to a single remote I/O unit. The standard implementation currently utilizes 10 Gbps Ethernet (802.3ae) for the link [401], however, there are two other lower performance variations. These are designated the “Low End” LE(dc) or low performance variations, typically suitable for embedded or cost sensitive installations:
The first low end variation is LE(dc) Triple link Aggregation 1 Gbps Ethernet (802.3ab) [402] for mapping to single-lane 2.5 Gbps PCI Express [403] at the remote I/O.
A second variation is LE(dc) Single link 1 Gbps Ethernet [404] for mapping single-lane 2.5 Gbps PCI Express [405] on a host to a legacy 32-bit/33 MHz PCI bus-based [406] remote I/O.
Software-only implementations of i-PCI enable i-PCI capability for applications where an i-PCI host bus adapter and/or remote bus adapter may not be desirable or feasible. Software-only implementations trade off relative high performance for freedom from physical hardware requirements and constraints. Software-only i-PCI also allows remote access to PCIe IOV resources via host-to-host network connections.
Automatic Configuration Protocols:
Automatic Configuration Protocols are part of the current art. There have been several automatic configuration protocols introduced over recent years, typically as a lower-level protocol that is part of a higher standard. These include:
Universal Serial Bus (USB) with its ability to automatically detect and configure devices via a “surprise” attach/detach event.
PCI and PCI Express, with its non-surprise or signaled “hot plug” insertion/removal capability.
Bootp, as a part of UDP, used as a means for a client to automatically have its IP address assigned.
Reverse Address Resolution Protocol (RARP), part of TCP/IP, used as a means for a host system to obtain its IP or network address based on its Ethernet or data link layer address.
Address Resolution Protocol (ARP), part of TCP/IP, used as a protocol by which a host may determine another host's Ethernet or data link layer address based on the IP or network address it has for the host.
Dynamic Host Configuration Protocol (DHCP), as part of TCP/IP, which allows network devices to be added through automating the assignment of various IP parameters, including IP addresses.
In the current state of the art, there are multiple I/O system virtualization standards. In order to make the best choice among the standards for a given application, the user has to inspect the computer architecture and network topology, note the physical location of the targeted I/O resources relative to the host, and understand the possible protocols that could be used to virtualize the I/O resources to achieve the best performance (i.e. highest data rate, lowest latency). The level of expertise and the time required to complete a study of the computer system and network to achieve the best data transfers is too time consuming. As a result, most users must rely on computer system and networking experts or simply default their configuration to a single I/O virtualization protocol—which typically is not ideal for all their I/O resources